LOANS - Past Due and Nonaccrual Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	$ 343	$ 308
Nonaccrual Including 90 Days or More Past Due	4,369	2,808
Total Past Due and Nonaccrual	11,078	7,516
Current	3,661,518	3,261,256
Total Loans	3,672,596	3,268,772
30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	4,465	3,780
60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	1,901	620
Commercial Real Estate | Mortgage loans
Past Due and Nonaccrual Loans
Total Loans	1,565,687	1,373,556
Commercial Real Estate | Mortgage loans | Owner occupied
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	225	253
Total Past Due and Nonaccrual	1,575	780
Current	529,513	509,618
Total Loans	531,088	510,398
Commercial Real Estate | Mortgage loans | Owner occupied | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	917	333
Commercial Real Estate | Mortgage loans | Owner occupied | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	433	194
Commercial Real Estate | Mortgage loans | Non-owner occupied
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	512	885
Total Past Due and Nonaccrual	610	885
Current	1,033,989	862,273
Total Loans	1,034,599	863,158
Commercial Real Estate | Mortgage loans | Non-owner occupied | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	98	0
Multi-family | Mortgage loans
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	0	0
Total Past Due and Nonaccrual	0	0
Current	812,174	585,827
Total Loans	812,174	585,827
Multi-family | Mortgage loans | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	0	0
Multi-family | Mortgage loans | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	0	0
Residential real estate mortgage loans | Mortgage loans
Past Due and Nonaccrual Loans
Total Loans	493,144	519,763
Residential real estate mortgage loans | Mortgage loans | Residential mortgage
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	2,086	199
Total Past Due and Nonaccrual	4,532	1,321
Current	419,980	447,194
Total Loans	424,512	448,515
Residential real estate mortgage loans | Mortgage loans | Residential mortgage | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	2,446	892
Residential real estate mortgage loans | Mortgage loans | Residential mortgage | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	0	230
Residential real estate mortgage loans | Mortgage loans | Home equity
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	343	308
Nonaccrual Including 90 Days or More Past Due	657	624
Total Past Due and Nonaccrual	2,354	1,965
Current	66,278	69,283
Total Loans	68,632	71,248
Residential real estate mortgage loans | Mortgage loans | Home equity | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	607	1,033
Residential real estate mortgage loans | Mortgage loans | Home equity | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	747	0
Commercial, industrial and agricultural loans
Past Due and Nonaccrual Loans
Total Loans	679,444	645,724
Commercial, industrial and agricultural loans | Secured
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	206	174
Total Past Due and Nonaccrual	417	700
Current	173,802	167,840
Total Loans	174,219	168,540
Commercial, industrial and agricultural loans | Secured | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	24	330
Commercial, industrial and agricultural loans | Secured | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	187	196
Commercial, industrial and agricultural loans | Unsecured
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	530	621
Total Past Due and Nonaccrual	1,313	1,729
Current	503,912	475,455
Total Loans	505,225	477,184
Commercial, industrial and agricultural loans | Unsecured | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	249	1,108
Commercial, industrial and agricultural loans | Unsecured | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	534	0
Real estate construction and land loans
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	123	0
Total Past Due and Nonaccrual	123	0
Current	97,188	123,393
Total Loans	97,311	123,393
Real estate construction and land loans | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	0	0
Real estate construction and land loans | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	0	0
Installment/consumer loans
Past Due and Nonaccrual Loans
>90 Days Past Due and Accruing	0	0
Nonaccrual Including 90 Days or More Past Due	30	52
Total Past Due and Nonaccrual	154	136
Current	24,682	20,373
Total Loans	24,836	20,509
Installment/consumer loans | 30-59 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	124	84
Installment/consumer loans | 60-89 Days Past Due
Past Due and Nonaccrual Loans
Total Past Due and Nonaccrual	$ 0	$ 0